Dataset: ice_thickness

Name: Ice thickness transect data from ARSV Laurence M. Gould LMG0106, LMG0205 in the Southern Ocean from 2001-2002 (SOGLOBEC project, Sea Ice Microbes project, Crabeater Seal Foraging project)
Published: 2020-01-22
Keywords: biota, oceans

Cite This Dataset

DOI:10.1575/1912/bco-dmo.3119.2

Spatial Extent: N:-66.3667 E:-67.8 S:-68.205 W:-70.725

Temporal Extent: 2001-07-28 - 2002-09-05

Project:

Foraging Ecology of Crabeater Seals (Lobodon Carcinophagus) (Crabeater Seal Foraging)

GLOBEC: Sea Ice Microbial Communities (Sea Ice Microbes)

U.S. GLOBEC Southern Ocean (SOGLOBEC)

Program:

U.S. GLOBal ocean ECosystems dynamics (U.S. GLOBEC)

Co-Principal Investigator:

Daniel P. Costa (University of California-San Diego, UCSD)

Chris H. Fritsen (Desert Research Institute, DRI)

BCO-DMO Data Manager:

Nancy Copley (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2020-01-22

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Ice thickness transect data from ARSV Laurence M. Gould LMG0106, LMG0205 in the Southern Ocean from 2001-2002 (SOGLOBEC project, Sea Ice Microbes project, Crabeater Seal Foraging project)

Abstract:

Ice thickness transect data from ARSV Laurence M. Gould LMG0106, LMG0205 in the Southern Ocean from 2001-2002 (SOGLOBEC project, Sea Ice Microbes project, Crabeater Seal Foraging project).

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Archival Copy

Version Date	Archive	Persistent Identifier	Date Assigned
2020-01-22	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.1575/1912/bco-dmo.3119.2	2020-01-22

Description

Related datasets:
ice properties, snow pits, sea ice, ice optics

Methods & Sampling

Ice floes were accessed from the LMG throughout the cruise for snow and ice studies that entailed ice and snow thickness transects, snow collections, ice core collections and brine collections. In addition CTD deployments and measures of bacterial and algal production were undertaken while on these long term ice stations. Thickness transects and snow pits were accomplished in conjunction with OG-241.

At the ice stations we measured ice thickness transects 20 m to 100 m in length. These transects were often located in an area under which the divers (BG-244) would be working. Along these transect lines we measured snow depth, slush depth (if present), depth ofthe wicked layer (the layer of snow above the slush layer which has absorbed moisture), ice thickness, freeboard (the distance from sea level to the ice surface), and ice surface temperature.

When time and ice conditions permitted, surveys of snow depth and ice thickness were conducted along 20 to 100-m-long lines. These survey lines were laid out on the ice and snow depth, freeboard, and ice thickness were measured every meter along the line. This was a team effort with individual people working a 1 m auger, a 2 m auger, snow pits, and an ice thickness tape. Ice cores were also taken to provide a detailed look at ice properties and structure. These surveys were conducted at 10 sites in 2001 and are summarized in the 2001 table. Surveys were conducted at 12 sites in 2002 and are summarized in the 2002 table.

Summary of 2001 survey sites	Summary of 2002 survey sites
Robert	Site 1
TR1	Site 6
TR2	Site 9-1
TR3	Site 9-2
TR4	Site 21-1
TR5	Site 21-2
TR10	Site 24-1
Billy	Site 24-2
Fernando	Site 29
Yoga	Site 30
	Site 31-1
	Site 31-2

Data Processing Description

These observations are being analyzed in conjunction with those collected by personnel on the N.B. Palmer to yield a regional ice maps. The summary data from the observations on the Gould show substantial amounts of open water were encountered during cruise as was evident from a large amount of time spent in the vicinity of the southern end of Adelaide Island where the reoccurring polyna predominated. Because of these operations, the operations are highly biased and significant editing of observations has to occur to account for reoccurring observations in the same region. Such editing and analysis are underway. Despite these known biases, the observations yield useful information in regards to the types of ice encountered. For instance, the average estimated ice thickness on ridged ice types was 54 cm while the average level ice thickness encountered was 38 cm (below). Snow thickness estimates yielded an average snow thickness of 11 cm with only 70.8% of the ice observed had snow (the remainder of the ice observed being nilas or young gray ice with new snow cover).

Summary statistics from sea ice observations aboard LMG01-06.

Total ice concentration (%):	82.18*
Open water within pack (%):	17.82*
Avg. level ice thickness (total area) cm:	31.52
Avg. level ice thickness (ice area) cm:	38.35
Fraction of surface area ridged:	0.05
Avg. ridged ice thickness (total area) cm:	44.5
Avg. ridged ice thickness (ice area) cm:	54.15
Avg. snow thickness (total area) cm:	9.05
Avg. snow thickness (ice area) cm:	11.01
Avg. snow thickness (snow covered area) cm:	15.55
Snow covered ice within pack (total area):	58.18
Snow free ice within pack (total area):	24
Percent ice with snow cover:	70.8
Percent ice with no snow:	29.2

Avg. albedo (total area)	0.55*

*biased by repetitive polyna observations

Summary statistics for observations taken during the LMG02-05 cruise.

Total ice concentration (%)	83.08
Open water within pack (%)	16.92
Avg. level ice thickness (total area) cm:	37.09
Avg. level ice thickness (ice area) cm:	44.65
Fraction of surface area ridged:	0.13
Avg. ridged ice thickness (total area) cm:	81
Avg. ridged ice thickness (ice area) cm:	97.5
Avg. snow thickness (total area) cm:	11.09
Avg. snow thickness (ice area) cm:	13.35
Avg. snow thickness (snow covered area) cm:	16.4
Snow covered ice within pack (% total area):	67.65
Snow free ice within pack (% total area):	15.43
Percent ice with snow cover:	81.43
Percent ice with no snow:	18.57
Avg. albedo (total area):	0.58

(from cruise reports, LMG0106, LMG0205)

BCO-DMO Processing Notes:
version 1 changes (2009-05-13):
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
version 2 changes (2020-01-22):
- changed lonitude values to negative for West locations
- changed date format from m/d/yyyy to yyyy-mm-dd

Data Files

File
ice_thickness.csv (Comma Separated Values (.csv), 4.85 KB) MD5:0468d6c60169656d5b167d487e05dabd Primary data file for dataset ID 3119

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Antarctic Sciences	ANT-9910098
NSF Antarctic Sciences	ANT-9981683

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
LMG0106		2001-07-21	ARSV Laurence M. Gould	Daniel P. Costa (Chief Scientist)	data info
LMG0205		2002-07-29	ARSV Laurence M. Gould	Daniel P. Costa (Chief Scientist)	data info

Instruments

None available yet

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
year	year, reported as YYYY, e.g. 1995		year
cruise_id	cruise designation; name		cruise_id
sta_id	station number; generally sequential; a unique number designating a general geographic location at which one or more sampling activities may occur		sta
sta_name	station name		sta
lat_start	latitude at starting time of measurement (west is negative)	decimal degrees	lat_start
lat_end	latitude at end time of measurement; in decimal degrees (negative denotes South)	decimal degrees	lat_end
lon_start	longitude at starting time of measurement (west is negative)	decimal degrees	lon_start
lon_end	longitude at end time of measurement; in decimal degrees (negative denotes West)	decimal degrees	lon_end
transect_id	transect number		transect
date_gmt	gmt month, day and year, usually as a text string, e.g. feb10_1995.		date_gmt
month_gmt	month of year, GMT time , i.e. 01-12		month_gmt
day_gmt	day, GMT time e.g. 22.		day_gmt
yrday_gmt	GMT day and decimal time, as 326.5 for the 326th day of the year, or November 22 at 1200 hours (noon).		yrday_gmt
transect_len	length along the transect at which the sample was taken.	meters	no_bcodmo_term
pcent_below_sealevl	percent of ice situated below sea level.	%	no_bcodmo_term
comments	free text comments		comment
snow_mean	mean snow thickness	centimeters	snow_thickness
snow_std	standard deviation of snow thickness	centimeters	snow_thickness
snow_min	minimum snow thickness	centimeters	snow_thickness
snow_max	maximum snow thickness	centimeters	snow_thickness
ice_mean	mean ice thickness	centimeters	ice_thickness
ice_std	standard deviation of ice thickness	centimeters	ice_thickness
ice_min	minimum ice thickness	centimeters	ice_thickness
ice_max	maximum ice thickness	centimeters	ice_thickness
freebd_mean	mean freeboard: the distance from sea level to the ice surface	centimeters	ice_thickness
freebd_std	standard deviation of freeboard: the distance from sea level to the ice surface	centimeters	ice_thickness
freebd_min	minimum freeboard: the distance from sea level to the ice surface	centimeters	ice_thickness
freebd_max	maximum freeboard: the distance from sea level to the ice surface	centimeters	ice_thickness
wetlayr_mean	mean wet layer: the layer of snow above the slush layer which has absorbed moisture	centimeters	snow_thickness
wetlayr_std	standard deviation of wet layer: the layer of snow above the slush layer which has absorbed moisture	centimeters	snow_thickness
wetlayr_min	minimum wet layer: the layer of snow above the slush layer which has absorbed moisture	centimeters	snow_thickness
wetlayr_max	maximum wet layer: the layer of snow above the slush layer which has absorbed moisture	centimeters	snow_thickness

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